Generally, the welding helmet serves to protect the eyes and faces of the worker during the welding or cutting process. The welding helmet includes the shading device for preventing the eyes of the worker from the blazing and harmful rays.
U.S. Pat. Nos. 5,533,206 and 6,070,264 disclose welding helmets provided with a shading device, what is called, a cartridge for automatically driving the shade during the welding process. However, there is a problem in that the shading device cannot easily attached or deattached to the welding helmets, so that the maintenance and repair are out of keeping.
In order to solve this problem, Korean Patent publication No. 10-2004-0082771 discloses another welding helmet for easily attaching and deattaching the shading device from the welding helmet.
In the meantime, in the maintenance of the welding helmet having the shading device, it is to be understood that the error rate of the LCD module is very low, but the bulk of the maintenance thereof is due to the error of the circuit portion.
Accordingly, the Korean Patent publication has a merit in that the shading device thereof can be easily attachable and deattachable to easily maintain and repair it. However, in the case of only the circuit portion failure, there is a problem in that the entire shading device is separated from the welding helmet in order to repair it. Especially, since the majority of the shading devices are exported to foreign countries at present, the foreign company must send the whole shading device to the domestic supplier in order to maintain and repair it. Also, there is a problem in that the shading device cannot be used during the maintenance and repair.
Also, where the circuit board cannot be used on account of the break down thereof, the LCD module of good condition should be changed, and in view of the fact that the LCD module has a large majority of the unit cost of the shading device, it causes a serious waste of resources as well as an additional cost unnecessary to the user.
Accordingly, in order to solve the conventional problems, there is an increased desire for the shading device in which it can maintain and repair harmoniously and prevent the unnecessary waste of resources.